It is known that obesity tends to cause many risk factors such as lipid metabolism abnormality, hypertension, glucose tolerance disorder, or the like. Total cholesterol and neutral lipids are increased, while the HDL (high-density lipoprotein) is decreased, in accordance with an increase in the accumulation of visceral fat. In addition, the qualitative abnormality of the LDL (low-density lipoprotein) is caused and the lipid metabolism is quantitatively and qualitatively influenced by visceral fat accumulation. Lipid metabolism abnormalities often occur in obese persons, and total cholesterol and neutral lipid content in the blood are particularly increased.
In recent years, lifestyle-related diseases such as diabetes have been increasing, and countermeasures for inhibiting such diseases have been reported. Obesity is considered to be a major cause of hyperlipidemia, hypertension, diabetes, and other lifestyle-related diseases. It is supposed that obesity should be prevented or the level of obesity should be decreased so as to prevent such diseases. In addition, obesity tends to be considered unfavorable in terms of personal appearance and beauty. Because of this, anorexia nervosa or hyperphagia is occasionally caused, and thereby medical treatment is required.
Thus, awareness of obesity is growing, and the Japan Society for the Study of Obesity defined in 2000 the “obesity symptom” associated with health disorders as a novel type of obesity and shows criteria for diagnosis of the obesity symptom. That is, the “obesity symptom” which causes disorders and therefore requires treatments has been distinguished from “obesity” in which body fat is accumulated, and the diagnosis thereof has been established. In addition, the criteria for diagnosis of “metabolic syndrome” which often causes lifestyle-related diseases was compiled in April, 2005. In the criteria, accumulation of visceral fat is required to be checked by measuring the waist perimeter. In addition, exercise therapy, diet modifications, and the like have been proposed in order to prevent obesity or reduce the level of obesity.
Milk tends not to be considered as a suitable food for reducing body-weight, since milk contains a fatty ingredient. In fact, milk is primarily a food for growing children, and contains lipids as an energy source. The lipids in milk are utilized for making butter and excessive intake of butter is considered to cause the obesity, and thereby milk tends also to be considered a fattening food.
However, babies drinking milk do not gain excessive weight, and it has not been reported that babies suffer from obesity which results in lifestyle-related diseases. That is, it has been suggested that milk contains a substance which enables effective utilization of lipids originally contained in milk as an energy source.
For example, Kawasaki et al., compared a milk-intake group which ingested 200 ml of milk per day to reduce body weight for four months while receiving dietary instruction and exercising with a control group which was not required to ingest milk, as shown in Non-Patent Document 1 described below. As a result, although there was almost no difference between the milk-intake group and the control group in terms of decreasing rate of body weight between before and after reducing the body weight for four-months, the ratio of the central adiposity in the milk-intake group was distinctly decreased in comparison with that of the control group. It has been reported that such an effect was considered to be exhibited by calcium or vitamin D contained in milk.
In addition, it has also been reported in the following Non-Patent Documents 2 and 3 that calcium in milk or a milk product has activities for reducing body weight.
In addition, the following Patent Document 1 discloses a food or drink for suppressing the blood lipid level containing a peptide obtained from hydrolyzing casein derived from milk with trypsin as an active ingredient thereof, relating to effects of a protein in milk or a hydrolysate or peptide thereof, for example. The following Patent Document 2 discloses the use of β-casein A2 for reducing cholesterol level, lipid level, triglyceride level, or the like, and a nutritional supplement containing β-casein A2. In addition, the following Patent Document 3 discloses a nutrition composition containing a milk mineral mixture and protein components such as κ-casein fragments 106-169, for effectively enhancing a decrease of body weight and/or suppressing an increase in body weight.
Patent Document 1 Japanese Unexamined Patent Application, First Publication No. H6-211690.
Patent Document 2 Published Japanese translation of No. 2006-501299 of PCT International Publication.
Patent Document 3 Published Japanese translation of No. 2006-507217 of PCT International Publication.
Non-Patent Document 1 Journal of Japanese Society of Nutrition and Food Science, Proceedings of the annual meeting 2006, Page 343.
Non-Patent Document 2 Journal of the American College of Nutrition, Vol. 19, 2000, Pages 754 to 760.
Non-Patent Document 3 FASEB Journal, Vol. 14, 2000, Pages 1132 to 1138.